Vehicle start system

Abstract

A power machine with an engine, a drive pump driven by the engine, and a drive motor operably coupled to the drive pump to receive a drive signal and provide a motor output to effect travel of the power machine is disclosed. A brake system on the power machine includes a brake for reducing or stopping movement of the power machine. A controller receives indications of a braking condition and whether the drive pump is outputting the drive signal. The controller determines in response to receipt of the indication of the braking condition whether the drive pump is outputting the drive signal to the drive motor shuts down the engine if the drive pump is providing the drive signal to the drive motor upon receipt of the braking condition.

What is claimed is: 
     
       1. A method of controlling braking of a power machine having an engine and a drive motor that is operably coupled to the engine and is configured to provide an output to effect travel of the power machine over a surface in response to a drive signal, the method comprising:
 running the engine; 
 providing a braking signal to energize a brake that is operably coupled to a tractive element on the power machine; 
 determining that a pump of the power machine is providing the drive signal to the drive motor while the braking signal is being provided; and 
 shutting down the engine when it is determined that the pump of the power machine is providing the drive signal to drive the motor while the braking signal is being provided. 
 
     
     
       2. The method of  claim 1 , and further comprising:
 receiving a signal from a brake input sensor indicating that the brake has been actuated. 
 
     
     
       3. The method of  claim 1 , and further comprising:
 receiving an input signal indicative of an intention to begin a braking condition. 
 
     
     
       4. The method of  claim 3 , wherein receiving the input signal includes receiving an indication of a start-up operation. 
     
     
       5. The method of  claim 3 , wherein receiving the input signal includes receiving a signal from a brake input sensor. 
     
     
       6. The method of  claim 1 , wherein determining that the pump of the power machine is providing the drive signal to the drive motor comprises receiving an indicator output from a pump actuation indicator operably coupled to at least one of the pump and a pump actuator. 
     
     
       7. The method of  claim 6 , wherein the pump actuator is a swash plate actuator coupled to the pump, and wherein receiving the indicator output comprises receiving an angle sensor output indicative of an angle of the swash plate, wherein determining that the pump of the power machine is providing the drive signal to the drive motor further comprises determining that the swash plate is in a neutral position or that the swash plate is in a non-neutral position which causes the pump to provide the drive signal to the drive motor. 
     
     
       8. The method of  claim 6 , wherein the pump actuation indicator is a sensor configured to provide the indicator output to be indicative of a position of the pump actuator. 
     
     
       9. The method of  claim 6 , wherein the pump actuation indicator is a flow sensor configured to sense flow of hydraulic fluid from the pump to the drive motor and to provide the indicator output to be indicative of the sensed flow. 
     
     
       10. A method of starting a power machine, the method comprising:
 receiving an indication of a start-up operation of an engine of the power machine; 
 determining whether a brake of the power machine is applied; 
 controlling an engine command signal to prevent the engine from starting if it is determined that the brake is not applied; 
 beginning an engine crank phase and controlling the engine command signal to start the engine if it is determined that the brake is applied; 
 determining during the engine crank phase whether a pump of the power machine is providing a drive signal to a drive motor of the power machine; 
 continuing the engine crank phase until the engine is started if it is determined that the pump of the power machine is not providing the drive signal to the drive motor; and 
 controlling the engine command signal to shut down the engine and prevent movement of the power machine if it is determined that the pump of the power machine is providing the drive signal to the drive the motor. 
 
     
     
       11. The method of  claim 10 , wherein determining during the engine crank phase whether the pump of the power machine is providing the drive signal to the drive motor comprises receiving an indicator signal from a pump actuation indicator operably coupled to at least one of the pump and a pump actuator and determining whether the pump is providing the drive signal to the drive motor based upon the indicator signal from the pump actuation indicator. 
     
     
       12. The method of  claim 11 , wherein the pump actuator is a swash plate actuator coupled to the pump, and wherein receiving the indicator signal from the pump actuation indicator comprises receiving a sensor output indicative of an angle of the swash plate, wherein determining during the engine crank phase whether the pump of the power machine is providing the drive signal to the drive motor further comprises determining based on the sensor output whether the swash plate is in a neutral position or whether the swash plate is in a non-neutral position which causes the pump to provide the drive signal to the drive motor. 
     
     
       13. The method of  claim 11 , wherein the pump actuation indicator is a sensor configured to provide the indicator signal such that the indicator signal is indicative of a position of the pump actuator. 
     
     
       14. The method of  claim 11 , wherein the pump actuation indicator is a flow sensor configured to sense flow of hydraulic fluid from the pump to the drive motor and to provide the indicator signal such that the indicator signal is indicative of the sensed flow. 
     
     
       15. A power machine comprising:
 an engine; 
 a drive pump operably coupled to and driven by the engine to selectively output a drive signal; 
 a drive motor operably coupled to the drive pump to receive the drive signal and to responsively provide a motor output to effect travel of the power machine over a surface; 
 a brake system comprising at least one brake configured to be selectively engaged to reduce movement of the power machine; and 
 a controller operably coupled to the brake system, to the drive pump and to the engine, wherein the controller is configured to:
 receive an indication of an application of the at least one brake and an indication of the drive pump outputting the drive signal; and 
 shut down the engine when each of the indication of the application of the at least one brake and the indication that the drive pump is outputting the drive signal is received. 
 
 
     
     
       16. The power machine of  claim 15 , wherein the controller is operably coupled to the drive pump through a pump actuation indicator configured to provide the indication of the drive pump is outputting the drive signal to the drive motor. 
     
     
       17. The power machine of  claim 16 , and further comprising a drive pump actuator operably coupled to the drive pump and configured to control the drive pump to selectively output the drive signal, and wherein the pump actuation indicator comprises a sensor configured to provide an output indicative of the position of the drive pump actuator as the indication of the drive pump is outputting the drive signal. 
     
     
       18. The power machine of  claim 16 , wherein the pump actuation indicator is a flow sensor configured to sense flow of hydraulic fluid from the drive pump to the drive motor and to provide the indication of the drive pump is outputting the drive signal based upon the sensed flow. 
     
     
       19. The power machine of  claim 15 , wherein the indication of the braking condition further comprises an indication of a start-up operation, and wherein the controller is further configured to, upon receiving the indication of a start-up operation, perform the steps comprising:
 determining that the at least one brake is engaged; 
 controlling the command signal to prevent the engine from starting if it is determined that the brake is not engaged; 
 beginning an engine crank phase and controlling the command signal to start the engine if it is determined that the brake is engaged; 
 determining during the engine crank phase that the drive pump is providing the drive signal; 
 continuing the engine crank phase until the engine is started if it is determined that the drive pump is not providing the drive signal to the drive motor; and 
 controlling the command signal to shut down the engine and prevent movement of the power machine if it is determined that the drive pump is providing the drive signal to the drive the motor. 
 
     
     
       20. The power machine of  claim 19 , wherein the controller is configured to provide the command signal to shut down the engine by stopping the engine crank phase.